I am running Windows 7 x64 (64 bit), but want to compile my programs in x86 (32 bit).
When Microsoft Visual C# 2010 Express is installed, it will as default compile to the same as the platform it is running on, which in my case would be x64.
To be able to easily change between them, you first go to Tools > Options
then select “Show all settings”
a lot more settings will now show. Navigate to “Projects and Solutions > General” and set a mark in “Show advanced build configurations”
after hitting OK you will see this fields, here you can select x64 or x86 from the drop-down.